Seal with installed space parts

ABSTRACT

To avoid the necessity of disassembling a drive for a pump to replace worn or defective parts of an end face shaft seal, provision is made for assembling around the shaft replacement parts for the seal at the time the original installation of the shaft seal is made. The subsequently worn or defective parts of the seal are destroyed and removed and the stored replacement parts are moved axially into place in he seal. The gland plate is split and removable to allow the replacement parts to pass through the gland plate to the seal. Worn parts which cannot be destroyed are moved to an annular storage space in housing provided for this purpose.

United States Patent Nappe [451 July 1 l, 1972 [s41 SEAL WITH INSTALLEDSPACE PARTS 3,147,981 9/1964 Woerheide ..277/9 [72] Inventor: William D.Nappe, Broomall Pa 3,441,284 4/1969 Murray et al. ..277/9 AssigneeiCrane Padang p y, Morton Grove, Primary Examiner-William E. WaynerAttorney-Charles F. Voytech [22] Filed: Sept. 3, 1970 ABSTRACT [21] AppLNo.: 69,352

To avoid the necessity of disassembling a drive for a pump toreplaceworn or defective parts of an end face shaft seal, U.S. provision ismade for around the shaft replacement 285/16 parts for the seal at thetime the original installation of the [-51 llll. Cl ..Fl6k 15/16 ShaftSeal is made. The subsequently worn or defective pans of [58] Field ofSearch ..277/9, 65 X, 81, 38 X; 285/15, the Sea] are destroyed andremoved d th stored replace- 285/16 17 ment parts are moved axially intoplace in he seal. The gland plate is split and removable to allow thereplacement parts to [56] References Cned pass through the gland plateto the seal. Worn parts which UNITED STATES PATENTS gannot bedesctircziyted air? moved to an annular storage space in ousln rov1 e ors u ose. 2,945,709 7/1960 Freed et al. ..277/9 X g p p rp 3,044,7877/1962 Derman ..277/83 4 Claims, 6 Drawing Figures SEAL WlTI-I INSTALLEDSPACE PARTS This invention relates to rotary mechanical seals of the endface type and particularly to a combination of such a seal with ahousing and gland plate which pennits storage of replacement parts forthe seal at the time the seal is installed.

It is well known that pumps for fluids driven from the exterior requirea seal in the pump housing around the pump drive shaft, the seal beingdisposed between the motor and pump. Modern speeds and pressures forpumps require the use of end face mechanical seals for this purpose.Such seals use rigid lapped washers and cooperating seats for therunning seal, and endless ring type flexible secondary seals. When thewasher, seat or secondary seal fails, the pump must be shut down and thedrive disassembled from the shaft so that the defective part can beremoved and the new part can be installed in its place.

The cost of replacing the defective seal parts is, of course,appreciable, but it may be small compared to the loss of productionwhile the pump is down, and to the cost of the rejected fluid resultingfrom incorrect processing caused while the pump is shutting down. Toreduce this cost, seal designers have resorted to split seals whichtheoretically can be moved and replaced without disassembling the drivefor the pump, but such seals are costly and are adaptable mainly tolarge shafts such as are used on ships. In the smaller shaft sizes wheresplit seals have not been practical, the use of two seals in tandem hasbeen proposed, the second seal serving as a standby until needed, thefirst seal, though defective, being allowed to remain in place until anopportune time is presented to remove it. The tandem seal design has notbeen very successful, partly because the second or standby seal must beinstalled with its running faces slightly separated to prevent wear, butwhen separated, they are exposed to ambient dirt particles which mayscar them and diminish or destroy their effectiveness.

The principal object of this invention is to provide means for replacingworn or defective parts of a rotary mechanical shaft seal with a minimumof down time and expense, and with maximum effectiveness of thereplacement arts.

As a more specific object, this invention has within its purview theinstallation of replacement parts for seals around a shaft at the timeof the original installation of an end face shaft seal around saidshaft, with means for effecting the replacement of the seal partswithout the disassembly of the drive for the shaft.

A further object of this invention is to provide an end face seal designand a design of the housing and gland plate associated with the sealwhich will permit the storage of spare washer, seat and secondary sealparts with complete protection of said spare parts while they are sostored.

These and other objects of this invention will become apparent from thefollowing detailed description of a preferred form of the invention whentaken together with the accompanying drawings in which:

FIG. 1 is an axial quarter section through an end face seal and spareparts therefor as installed in a housing;

FIG. 2 is an end view in section, on a reduced scale, of the seal andhousing of FIG. 1, the section being taken along line 2-2 of FIG. 1;

FIG. 3 is a view in section of the seal and housing of FIG. 1 showingthe seal and spare parts as they are being installed;

FIG. 4 is an axial quarter sectional view of the seal of FIG. 1 afterthe spare parts have been installed;

FIG. 5 is an end view in section, on a reduced scale, of the seal ofFIG. 1, the section being taken along line 5-5 of FIG. 1; and

FIG. 6 is an axial quarter section of a modification of the seal andspare parts of FIG. 1.

The present invention is more readily adaptable to end face seals whichuse a solid ring-type secondary seal, and the seal selected toillustrate this invention is therefore one which uses a wedge-shapedsecondary seal made from polytetrafluorethylene. A rigid seat is usedfor the seal, the seat'being either metal or ceramic and having a lappedface of a sealing washer made of a different material. The washer isdriven by an axially split retainer secured to a sleeve clamped orpressed on the pump shaft. The seal cavity in the pump housing is longerthan required by the seal so that storage space can be provided for theseat after it has become worn and is discarded.

The gland plate for the housing is split axially and has a hublike axialextension defining a second seal cavity in which are retained as spareparts a sealing washer, a secondary seal for the sealing washer, a seatand a secondary seal for the seat.

To replace the worn seat, sealing washer and secondary seal inaccordance with this invention, the split gland plate is removed, thesleeve and seal parts thereon are pulled out, the split retainer isremoved to gain access to the wedge-shaped secondary seal which is cutopen and removed. The sealing washer is broken and removed, and the wornmetal seat, which cannot readily be destroyed, is slid over the sleeveinto the axial space in the seal cavity behind the seal. The sparesecondary seal and washer are then moved axially to the positions oftheir destroyed counterparts and the retainer is reassembled aroundthem. The sleeve is pushed back to its old position on the shaft and thespare seat is advanced into the housing in sealing contact with thesealing washer. Finally, the split gland plate is reassembled on thehousing. At no time during the removal of the worn seal parts and theirreplacement is it necessary to remove any portion of the shaft or thedrive therefor.

Referring now to the drawings for a detailed description of theinvention and particularly to FIG. 1, a housing of a pump or the like isshown at 10, said housing having an opening 11 through which extends ashaft 12 by which a pump impeller or other fluid-moving mechanism (notshown) is driven from the exterior of housing 10. In the form selectedto illustrate this invention, housing 10 is provided with a flange 13and is formed Surrounding shaft 12 and disposed partly within sealchamber 15 is a sleeve 16 which is sealed with respect to shaft 12 atits left-hand end, as viewed in FIG. 1, by an O-ring 17. At itsright-hand end, as viewed in FIG. 1, sleeve 16 has an axial slot 18 andis formed with a split flange 19 extending radially upwardly adjacentslot 18, the ends of the flange being adapted to be drawn together by asuitable bolt 20 or other threaded device to clamp said right-hand endof sleeve 16 to shaft 12 against axial or rotational movement withrespect thereto.

Seal chamber 15 is partly closed by a gland plate 21 which is split intotwo halves in an axial direction so that said plate may be removed fromaround shaft 12 without freeing the end of said shaft from its motor orother driving device. Said gland plate 21 is fastened by means of bolts22 to flange 13 of housing 10. It may be understood that the twoportions of the split gland plate need not be of equal size, it beingonly necessary that the smaller part be at least equal in width to thediameter of sleeve 16 so that the large portion can be removed fromaround said sleeve.

Within seal chamber 15 is disposed a typical seal 23 of the end facetype. Said seal 23 may be comprised of a sealing washer 24, a retainer25, a secondary seal 26, a series of helical springs 27, retained insuitable recesses 28 in retainer 25, and a washer 29 which serves totransmit the spring pressure to secondary seal 26.

Washer 24 is an endless ring of carbon or other frangible material.Secondary seal 26 may be a wedge-shaped endless ring ofpolytetrafluoroethylene. Spring washer 29 may be an endless metallicwasher made of brass or other material compatible with the fluid to besealed. Retainer 25 is split into two halves in an axial direction, saidhalves being held together by clamping screws 30. Said retainer 25 islikewise made of either brass or other metal which is compatible withthe fluid being sealed. Retainer 25, being split, can also be removedfrom around shaft 12 without disconnecting said shaft from its drive.

with a recess 14 which, with shaft 12, defines a seal chamber Seal 23 ismounted on a smooth cylindrical surface 31 on the exterior of sleeve 16,said sleeve being of reduced diameter, or stepped from a point justwithin washer 24 to the flange 19 as shown at 32.

Sealing washer 24 has a radially disposed sealing surface 33 which is inrunning sealing engagement with a corresponding radially disposedsealing surface 34 on an endless metallic seal seat 35. Said seat 35 issealed with respect to recess 14 by an O-ring 36. Seal seat 35 isrestrained from rotation with washer 24 by a drive pin 37 extendingaxially thereinto from gland plate 21. The inner diameter 38 of sealseat 35 is greater than the outer diameter of cylindrical surface 31 onsleeve 16.

Gland plate 21 has an axial extension or hub 52 the inner diameter 39 ofwhich is substantially equal to or slightly greater than, the outerdiameter of sealing washer 24 and the outer diameter of spring washer29. A counterbore 40 in hub 52 is of substantially the same diameter as,or slightly greater than, the diameter of recess 14. The axial length ofthe portion of hub 52 having the inner diameter 39 is substantiallyequal to the axial length of an assembled sealing washer 24, secondaryseal ring 26, and spring washer 29, and the axial length of counterbore40 is substantially equal to the axial length of seal seat 35 plus asufficient length to permit the use of a snap ring 41.

Thus a spare spring washer 42, secondary seal 43, sealing washer 44,seal seat 45 and O-ring 46 may be mounted in the gland plate 21 betweenseal seat 35 and snap ring 41 in counterbore 40. Inasmuch as sleeve 16is of reduced diameter within gland plate 21, there is no contactbetween the spare parts, which are non-rotably fixed to gland plate 21,and sleeve 16, which is clamped to, and rotable with, shaft 12, andhence the spare parts will not be worn by sleeve 16.

Assuming now that sealing washer 24, secondary seal 26, and seal seat 35have become worn to the point that excessive leakage of the fluid in thehousing occurs, either at the seal faces 33, 34 or at the secondary seal26, it becomes necessary to remove the worn seal parts and replace themwith new parts. This can be done with the construction shown in FIG. 1without disassembling the drive shaft 12 by first removing bolts 22 andthen removing the split gland plate 21 from around shaft 12. This freesthe spare spring washer 42, secondary seal 43, sealing washer 44, sealseat 45 and seal seat ring 46.

Next, bolt 20 is loosened to remove the clamping pressure from sleeve16, and said sleeve is then moved to the right as viewed in FIG. 3 outof seal chamber 15. Seal 23 and its seat 35, together with the old sealseat O-ring 36, are moved outwardly with sleeve 16 as well as the spareparts 42, 43, 44, 45 and 46. Retainer 25 is now accessible from theexterior of housing and the clamping screws 30 are removed so that splitretainer 25 may be removed from around sleeve 16. This also makessealing washer 25, secondary seal 26, and spring washer 29 accessible.These elements are then broken up or cut so that they may be removedcompletely from around sleeve 16. It is now possible for old seat 35,which cannot be readily destroyed nor moved past flange 19, and itsO-ring 36, to be moved to the left as viewed in FIG. 3 into a space atthe bottom of recess 14 between the inner end of sleeve 16 and thebottom of said recess 14. O-ring 36 helps hold ring 45 frictionally inplace at the bottom of recess 14.

With seal seat 35 located at the bottom or recess 14 as shown in dottedoutline in FIG. 3 the replacement seal parts may now be installed onsleeve 16.

The spare parts 42, 43, and 44 are moved back around surface 31 to thepositions occupied by their corresponding parts 29, 26, 24 when thelatter were first installed as new seal parts, and split retainer 25 isreassembled around the new parts and clamped into place upon surface 31.Seal seat 45 is at this point loose on sleeve 16, just as the originalseal seat 35 was loose around sleeve 16 at this stage of the assembly ofthe seal on sleeve 16. Said sleeve 16 is then slid to the left as viewedin FIG. 3 into recess 44 to its previous position on shaft 12 and glandplate 21 is then bolted to flange 13 between seat 45 and sleeve flange19, the gland plate, as in the original installation causing the newseat 45 to bear against sealing washer 44 and the pressure of thesprings 27 to assure firm running sealing contact between the radialface 47 on washer 44 and the radial face 48 on seal seat 45. The sealingarrangement now resem bles that shown in FIG. 4.

It may be noted that the presence of the old seal seat in the bottom ofseal chamber 15 does not interfere in any way with the operation of theseal. It may be noted further that the entire change of worn parts forthe new parts previously stored in gland plate 21 was effected withoutin any way requiring the threading of any part over the end of shaft 12.Thus it was not necessary to disconnect the shaft from its drive toreplace the worn parts with new parts.

In the embodiment. just described the spare parts were retained in thegland plate and hence did not rotate. In the modification shown in FIG.6 the spare parts are retained in a cup-shaped molded foam plasticmember 49 which fits closely over the spare parts and over the sleeve50. Said sleeve 50 is of constant diameter throughout its length toprovide support for the spare parts 42-45. In the FIG. 6 form, the glandplate 51 is likewise split, but it contains no axial extension since itis not required to provide a chamber for holding the spare parts. Theplastic retainer 49 is expendable in the sense that it may be readilycut and ripped away from the spare parts when it is desired to use themto replace the worn parts within seal chamber 15. In all other respectsthe method of removing the worn parts and replacing them with the newparts is the same as that used with the FIG. 1 form so that the ultimateresult resembles that of FIG. 4.

The foregoing invention is applicable to seals of the end face typeusing various forms of expendable parts. Thus the secondary seal may bean O-ring, or a V-ring, or any of the known forms of packing ringscapable of functioning in the environment and physical conditions foundin cavity 15. In some instances seat ring 45 may be made of ceramic andhence can, if desired, be broken up and removed rather than stored atthe bottom cavity 15. It is also contemplated that extension 52 on glandplate 21 may be a separate piece made of foam rubber and simply adheredto a flat gland plate such as 51 in FIG. 6.

It is understood, thus, that the foregoing description is merelyillustrative of preferred embodiments of the invention and that thescope of the invention therefore is not to be limited thereto, but is tobe determined by the appended claims.

I claim:

1. The combination with relatively rotatable elements comprising ahousing and a shaft passing through said housing, said housing having aseal cavity around said shaft, of seal means in the cavity in sealingrelation to the housing and shaft, said seal means having an expendablepart, a duplicate expendable part disposed around the shaft in axiallyspaced relation to said seal means, means on one of said elementssupporting said duplicate part in fixed relation to said one of saidelements, a split abutment between said seal means and duplicate pan,said abutment being removable radially of said shaft, whereby to makethe expendable part of the seal means accessible for removal andreplacement by said duplicate expendable part, a sleeve on said shaftslidable axially thereon, means for sealing said sleeve with respect tosaid shaft and means for securing the sleeve to the shaft for rotationtherewith, said seal means being mounted on said sleeve and said sleevepassing through said duplicate expendable part.

2. The combination described in claim 1, said expendable part comprisinga frangible sealing washer, and said seal means having an expendableremovable secondary seal and an expendable rigid washer, said cavitybeing longer than said sealing means, and said expendable rigid washerbeing movable into said cavity beyond said sealing means when thesecondary seal and frangible sealing washer are expended.

3. The combination described in claim 2, said seal means comprising asplit retainer, axially directed spring means in the retainer adapted toexert axial pressure upon the secondary seal, and means for driving theretainer from the shaft.

said seal means comprising further a split retainer adapted to be fixedto said sleeve, said frangible washer and secondary seal being disposedwithin said retainer, and there being a duplicate metal seal seat and aduplicate secondary seal disposed around said shaft in axially spacedrelation to said seal means.

2223? UNITED STATES PATENT OFFICE CERTIFICATE ()F CORRECTIQN rate No.3,675, 933 Dated Juli 11, 197.2

lnventor(s) William D. Nappe It is' certified that error appears in theabove-identified patent and that; said Letters Patent are herebycorrected as shown below:

In Title (P. lfChahgeTSPACE" to--S PARE.

In Abstract line 7 before "seal" change "he" to -the.

Col. 1 in Titl change "SPACE" to SPARE Signed and sealed hie 26th day ofDecember 1972.

(SEAL) EDWARD MQFLETCHER,JR. ROB IR'L' GO'ITSCHAIK Attes ing Officer.

Commissioner of Pa ents

1. The combination with relatively rotatable elements comprising ahousing and a shaft passing through said housing, said housing having aseal cavity around said shaft, of seal means in the cavity in sealingrelation to the housing and shaft, said seal means having an expendablepart, a duplicate expendable part disposed around the shaft in axiallyspaced relation to said seal means, means on one of said elementssupporting said duplicate part in fixed relation to said one of saidelements, a split abutment between said seal means and duplicate part,said abutment being removable radially of said shaft, whereby to makethe expendable part of the seal means accessible for removal andreplacement by said duplicate expendable part, a sleeve on said shaftslidable axially thereon, means for sealing said sleeve with respect tosaid shaft and means for securing the sleeve to the shaft for rotationtherewith, said seal means being mounted on said sleeve and said sleevepassing through said duplicate expendable part.
 2. The combinationdescribed in claim 1, said expendable part comprising a frangiblesealing washer, and said seal means having an expendable removablesecondary seal and an expendable rigid washer, said cavity being longerthan said sealing means, and said expendable rigid washer being movableinto said cavity beyond said sealing means when the secondary seal andfrangible sealing washer are expended.
 3. The combination described inclaim 2, said seal means comprising a split retainer, axially directedspring means in the retainer adapted to exert axial pressure upon thesecondary seal, and means for driving the retainer from the shaft. 4.The combination described in claim 1, said expendable part comprising afrangible sealing washer and said seal means having an expendableremovable secondary seal and an expendable metal seal seat adapted tohave running sealing engagement with said frangible sealing washer,means for fixing said metal seat against relative rotation with saidhousing, said abutment comprising a split gland plate, an axiallyslidable sleeve on said shaft, means for fixing said sleeve to saidshaft, said seal means comprising further a split retainer adapted to befixed to said sleeve, said frangible washer and secondary seal beingdisposed within said retainer, and there being a duplicate metal sealseat and a duplicate secondary seal disposed around said shaft inaxially spaced relation to said seal means.